gdb/python/py-membuf.c

   1 /* Python memory buffer interface for reading inferior memory.
   2
   3    Copyright (C) 2009-2024 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "python-internal.h"
  21
  22 struct membuf_object {
  23   PyObject_HEAD
  24
  25   /* Pointer to the raw data, and array of gdb_bytes.  */
  26   void *buffer;
  27
  28   /* The address from where the data was read, held for mbpy_str.  */
  29   CORE_ADDR addr;
  30
  31   /* The number of octets in BUFFER.  */
  32   CORE_ADDR length;
  33 };
  34
  35 extern PyTypeObject membuf_object_type
  36     CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("membuf_object");
  37
  38 /* Wrap BUFFER, ADDRESS, and LENGTH into a gdb.Membuf object.  ADDRESS is
  39    the address within the inferior that the contents of BUFFER were read,
  40    and LENGTH is the number of octets in BUFFER.  */
  41
  42 PyObject *
  43 gdbpy_buffer_to_membuf (gdb::unique_xmalloc_ptr<gdb_byte> buffer,
  44                         CORE_ADDR address,
  45                         ULONGEST length)
  46 {
  47   gdbpy_ref<membuf_object> membuf_obj (PyObject_New (membuf_object,
  48                                                      &membuf_object_type));
  49   if (membuf_obj == nullptr)
  50     return nullptr;
  51
  52   membuf_obj->buffer = buffer.release ();
  53   membuf_obj->addr = address;
  54   membuf_obj->length = length;
  55
  56   return PyMemoryView_FromObject ((PyObject *) membuf_obj.get ());
  57 }
  58
  59 /* Destructor for gdb.Membuf objects.  */
  60
  61 static void
  62 mbpy_dealloc (PyObject *self)
  63 {
  64   xfree (((membuf_object *) self)->buffer);
  65   Py_TYPE (self)->tp_free (self);
  66 }
  67
  68 /* Return a description of the gdb.Membuf object.  */
  69
  70 static PyObject *
  71 mbpy_str (PyObject *self)
  72 {
  73   membuf_object *membuf_obj = (membuf_object *) self;
  74
  75   return PyUnicode_FromFormat (_("Memory buffer for address %s, \
  76 which is %s bytes long."),
  77                                paddress (gdbpy_enter::get_gdbarch (),
  78                                          membuf_obj->addr),
  79                                pulongest (membuf_obj->length));
  80 }
  81
  82 static int
  83 get_buffer (PyObject *self, Py_buffer *buf, int flags)
  84 {
  85   membuf_object *membuf_obj = (membuf_object *) self;
  86   int ret;
  87
  88   ret = PyBuffer_FillInfo (buf, self, membuf_obj->buffer,
  89                            membuf_obj->length, 0,
  90                            PyBUF_CONTIG);
  91
  92   /* Despite the documentation saying this field is a "const char *",
  93      in Python 3.4 at least, it's really a "char *".  */
  94   buf->format = (char *) "c";
  95
  96   return ret;
  97 }
  98
  99 /* General Python initialization callback.  */
 100
 101 static int CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION
 102 gdbpy_initialize_membuf (void)
 103 {
 104   membuf_object_type.tp_new = PyType_GenericNew;
 105   return gdbpy_type_ready (&membuf_object_type);
 106 }
 107
 108 GDBPY_INITIALIZE_FILE (gdbpy_initialize_membuf);
 109
 110 \f
 111
 112 static PyBufferProcs buffer_procs =
 113 {
 114   get_buffer
 115 };
 116
 117 PyTypeObject membuf_object_type = {
 118   PyVarObject_HEAD_INIT (nullptr, 0)
 119   "gdb.Membuf",                   /*tp_name*/
 120   sizeof (membuf_object),         /*tp_basicsize*/
 121   0,                              /*tp_itemsize*/
 122   mbpy_dealloc,                   /*tp_dealloc*/
 123   0,                              /*tp_print*/
 124   0,                              /*tp_getattr*/
 125   0,                              /*tp_setattr*/
 126   0,                              /*tp_compare*/
 127   0,                              /*tp_repr*/
 128   0,                              /*tp_as_number*/
 129   0,                              /*tp_as_sequence*/
 130   0,                              /*tp_as_mapping*/
 131   0,                              /*tp_hash */
 132   0,                              /*tp_call*/
 133   mbpy_str,                       /*tp_str*/
 134   0,                              /*tp_getattro*/
 135   0,                              /*tp_setattro*/
 136   &buffer_procs,                  /*tp_as_buffer*/
 137   Py_TPFLAGS_DEFAULT,             /*tp_flags*/
 138   "GDB memory buffer object",     /*tp_doc*/
 139   0,                              /* tp_traverse */
 140   0,                              /* tp_clear */
 141   0,                              /* tp_richcompare */
 142   0,                              /* tp_weaklistoffset */
 143   0,                              /* tp_iter */
 144   0,                              /* tp_iternext */
 145   0,                              /* tp_methods */
 146   0,                              /* tp_members */
 147   0,                              /* tp_getset */
 148   0,                              /* tp_base */
 149   0,                              /* tp_dict */
 150   0,                              /* tp_descr_get */
 151   0,                              /* tp_descr_set */
 152   0,                              /* tp_dictoffset */
 153   0,                              /* tp_init */
 154   0,                              /* tp_alloc */
 155 };